It is well known that modern industry is placing greater emphasis on Quality Control than ever before. In an effort to enhance the on-line quality control capabilities of their production machines, manufacturers are turning more and more to Machine Vision. Unfortunately most established production machines were not designed with Machine Vision in mind, therefore it is not always possible for a video camera to obtain a clear unobstructed view of the product due to mechanical restrictions. Mechanical re-design of the machine would be intricate, costly and not entirely effective.
In a cigarette packaging machine a bundle of twenty cigarettes are first wrapped in a paper jacket, then proceed to an overwrap station where the packages receive an outer jacket of Cellophane which is folded and heat sealed on three sides; the packages then travel only a short distance before they are inserted into cartons.
It is necessary for a Machine Vision System to perform final quality checks on the cigarette packages after they emerge from the heat sealers and before they are inserted into cartons; the following list summarizes the type of defects which are looked for in this area:
Crumpled packages PA1 Missing Cellophane PA1 Imperfect side seals PA1 Open Cellophane end flaps PA1 Wrinkled Cellophane PA1 Missing or misplaced tear tape
In prior machines some of the package surfaces which must be viewed by the video cameras in order to detect the above mentioned defects are not clearly visible due to the mechanical obstructions in the packaging machine conveyor path.
FIG. 1 illustrates the output area of a conventional cigarette packaging machine where pairs of cigarette packages 10 having been wrapped in cellophane, emerge from a heat-sealer 12 and move along a first predetermined path 14 into one of eight receptacles 16 in a rotatable turret 18 which is rotated in intermittent increments of 45.degree. by a mechanical indexing mechanism 22, thus sliding the packages over the fixed baseplate 20 and along a second path to a transfer position 28 where they are transferred by a mechanical pusher 30 to a third predetermined path 14a from where they are inserted into cartons. Any packages which have been found to be defective by certain up-stream sensors (not shown) will be rejected from the turret at the reject station 24. At this station the fixed base plate 20 has a cut-out which is larger than the packages; this gap is normally bridged by a movable plate 26 which is automatically moved aside when a known defective package is indexed into the reject station 24 allowing the defective package to drop into a defective product container 32.